Numb or tingling toes are a little-known sign of a disabling vitamin deficiency suffered by around one in 10 women, experts say.
Vitamin B12 deficiency can cause a range of symptoms including brain fog, low mood and extreme exhaustion.
The problems occur because the vitamin, which is abundant in liver and eggs, is crucial for healthy blood circulation, as well as nerve and brain function.
The telltale signs are often dismissed as anxiety, the menopause or even dementia.
Now, experts have highlighted a physical change that might help patients better tell if they’re at risk.
‘The feet sit at the very end of the body’s nerve and blood supply, so they’re the first to feel the effects when metabolism or circulation is compromised,’ said Marion Yau, a podiatrist at Harley Medical Foot and Nail Clinic.
‘Nutrient deficiencies typically affect the longest nerves in the body first – including those running down to the toes.’
Common warning signs include burning sensations, numbness and tingling in the feel, she said.
A burning sensation in your feet and tngling in your toes may seem minor, but they can signal serious underlying problems elsewhere in the body
Vitamin B12 is used by the body to produce myelin, the protective coating that surrounds nerve cells.
Without it, this protective layer can break down, disrupting nerve signals and triggering the unusual sensations in the feet.
‘Circulation plays a big part too,’ Ms Yau added. ‘A lack of Vitamin B12 can reduce the blood cells’ oxygen carrying abilities, which shows up in the feet as changes in colour, persistent coldness and wounds that are slow to heal.’
Current figures estimate that about one in five adults over the age of 50 are affected by the vitamin deficiency. The condition is far more common in older age as our ability to absorb the nutrient deteriorates with time.
A recent study published in the British Medical Journal suggested the problem is increasing, the number of annual vitamin B12 prescriptions in England doubling over the past decade, from two and a half million to five million.
Experts say many more are suffering needlessly due to underdiagnosis, partly because symptoms develop slowly over several years.
As a result, millions of Britons could be living with deficiencies for years – risking irreversible nerve damage and even deadly heart failure.
‘That’s why it is always important to discuss any changes in your feet with your GP, who will be able to test for any underlying issues,’ Ms Yau said.
Type 2 diabetes develops when your body stops responding to, or producing enough of, the hormone insulin, causing blood sugar levels to rise
Vitamin deficiency is not the only possible explanation for burning or numb feet. Another possible cause is uncontrolled type 2 diabetes.
Type 2 diabetes – when blood sugar becomes dangerously unstable – can lead to severe complications including heart disease, stroke and even dementia.
Researchers have consistently found that people with high blood levels of uric acid – which form painful crystals that settle in the big toe joint – are more likely to develop type 2 diabetes.
Uric acid is a natural waste product excreted by the kidneys, so an excess may indicate an underlying metabolic issue like uncontrolled diabetes.
A build-up of the crystals in the toe triggers the burning, hot and tingling sensation.
A podiatrist can treat the pain by prescribing painkillers like Ibuprofen to reduce inflammation, but Ms Yau said patients should also see their GP, who can administer a blood test to check glucose levels.
Lifestyle changes including eating a healthy diet and exercising regularly can help manage and even reverse the condition.
Risk of developing the disease increases with age, but now rates among younger adults, particularly women, are driving the trend, according to NHS England estimates.
Around five million people in the UK are thought to be living with type 2 diabetes, while many thousands more remain undiagnosed.
Of these, 12,000 are under the age of 30, Imperial College London analyses suggest.
When it develops at a younger age, the disease tends to be more aggressive, increasing the risk of devastating complications and premature death.
While obesity drugs – such as Wegovy and Mounjaro – might help, experts say knowing the warning signs is crucial.
Common symptoms include fatigue, excessive thirst and needing to urinate more often.
